summaryrefslogtreecommitdiff
path: root/fs/smb/server/transport_tcp.c
blob: 002a3f0dc7c5880b61045cf7f10f7e078b85d6a9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *   Copyright (C) 2016 Namjae Jeon <linkinjeon@kernel.org>
 *   Copyright (C) 2018 Samsung Electronics Co., Ltd.
 */

#include <linux/freezer.h>

#include "smb_common.h"
#include "server.h"
#include "auth.h"
#include "connection.h"
#include "transport_tcp.h"

#define IFACE_STATE_DOWN		BIT(0)
#define IFACE_STATE_CONFIGURED		BIT(1)

static atomic_t active_num_conn;

struct interface {
	struct task_struct	*ksmbd_kthread;
	struct socket		*ksmbd_socket;
	struct list_head	entry;
	char			*name;
	struct mutex		sock_release_lock;
	int			state;
};

static LIST_HEAD(iface_list);

static int bind_additional_ifaces;

struct tcp_transport {
	struct ksmbd_transport		transport;
	struct socket			*sock;
	struct kvec			*iov;
	unsigned int			nr_iov;
};

static struct ksmbd_transport_ops ksmbd_tcp_transport_ops;

static void tcp_stop_kthread(struct task_struct *kthread);
static struct interface *alloc_iface(char *ifname);

#define KSMBD_TRANS(t)	(&(t)->transport)
#define TCP_TRANS(t)	((struct tcp_transport *)container_of(t, \
				struct tcp_transport, transport))

static inline void ksmbd_tcp_nodelay(struct socket *sock)
{
	tcp_sock_set_nodelay(sock->sk);
}

static inline void ksmbd_tcp_reuseaddr(struct socket *sock)
{
	sock_set_reuseaddr(sock->sk);
}

static inline void ksmbd_tcp_rcv_timeout(struct socket *sock, s64 secs)
{
	lock_sock(sock->sk);
	if (secs && secs < MAX_SCHEDULE_TIMEOUT / HZ - 1)
		sock->sk->sk_rcvtimeo = secs * HZ;
	else
		sock->sk->sk_rcvtimeo = MAX_SCHEDULE_TIMEOUT;
	release_sock(sock->sk);
}

static inline void ksmbd_tcp_snd_timeout(struct socket *sock, s64 secs)
{
	sock_set_sndtimeo(sock->sk, secs);
}

static struct tcp_transport *alloc_transport(struct socket *client_sk)
{
	struct tcp_transport *t;
	struct ksmbd_conn *conn;

	t = kzalloc(sizeof(*t), GFP_KERNEL);
	if (!t)
		return NULL;
	t->sock = client_sk;

	conn = ksmbd_conn_alloc();
	if (!conn) {
		kfree(t);
		return NULL;
	}

	conn->transport = KSMBD_TRANS(t);
	KSMBD_TRANS(t)->conn = conn;
	KSMBD_TRANS(t)->ops = &ksmbd_tcp_transport_ops;
	return t;
}

static void free_transport(struct tcp_transport *t)
{
	kernel_sock_shutdown(t->sock, SHUT_RDWR);
	sock_release(t->sock);
	t->sock = NULL;

	ksmbd_conn_free(KSMBD_TRANS(t)->conn);
	kfree(t->iov);
	kfree(t);
}

/**
 * kvec_array_init() - initialize a IO vector segment
 * @new:	IO vector to be initialized
 * @iov:	base IO vector
 * @nr_segs:	number of segments in base iov
 * @bytes:	total iovec length so far for read
 *
 * Return:	Number of IO segments
 */
static unsigned int kvec_array_init(struct kvec *new, struct kvec *iov,
				    unsigned int nr_segs, size_t bytes)
{
	size_t base = 0;

	while (bytes || !iov->iov_len) {
		int copy = min(bytes, iov->iov_len);

		bytes -= copy;
		base += copy;
		if (iov->iov_len == base) {
			iov++;
			nr_segs--;
			base = 0;
		}
	}

	memcpy(new, iov, sizeof(*iov) * nr_segs);
	new->iov_base += base;
	new->iov_len -= base;
	return nr_segs;
}

/**
 * get_conn_iovec() - get connection iovec for reading from socket
 * @t:		TCP transport instance
 * @nr_segs:	number of segments in iov
 *
 * Return:	return existing or newly allocate iovec
 */
static struct kvec *get_conn_iovec(struct tcp_transport *t, unsigned int nr_segs)
{
	struct kvec *new_iov;

	if (t->iov && nr_segs <= t->nr_iov)
		return t->iov;

	/* not big enough -- allocate a new one and release the old */
	new_iov = kmalloc_array(nr_segs, sizeof(*new_iov), GFP_KERNEL);
	if (new_iov) {
		kfree(t->iov);
		t->iov = new_iov;
		t->nr_iov = nr_segs;
	}
	return new_iov;
}

static unsigned short ksmbd_tcp_get_port(const struct sockaddr *sa)
{
	switch (sa->sa_family) {
	case AF_INET:
		return ntohs(((struct sockaddr_in *)sa)->sin_port);
	case AF_INET6:
		return ntohs(((struct sockaddr_in6 *)sa)->sin6_port);
	}
	return 0;
}

/**
 * ksmbd_tcp_new_connection() - create a new tcp session on mount
 * @client_sk:	socket associated with new connection
 *
 * whenever a new connection is requested, create a conn thread
 * (session thread) to handle new incoming smb requests from the connection
 *
 * Return:	0 on success, otherwise error
 */
static int ksmbd_tcp_new_connection(struct socket *client_sk)
{
	struct sockaddr *csin;
	int rc = 0;
	struct tcp_transport *t;
	struct task_struct *handler;

	t = alloc_transport(client_sk);
	if (!t) {
		sock_release(client_sk);
		return -ENOMEM;
	}

	csin = KSMBD_TCP_PEER_SOCKADDR(KSMBD_TRANS(t)->conn);
	if (kernel_getpeername(client_sk, csin) < 0) {
		pr_err("client ip resolution failed\n");
		rc = -EINVAL;
		goto out_error;
	}

	handler = kthread_run(ksmbd_conn_handler_loop,
			      KSMBD_TRANS(t)->conn,
			      "ksmbd:%u",
			      ksmbd_tcp_get_port(csin));
	if (IS_ERR(handler)) {
		pr_err("cannot start conn thread\n");
		rc = PTR_ERR(handler);
		free_transport(t);
	}
	return rc;

out_error:
	free_transport(t);
	return rc;
}

/**
 * ksmbd_kthread_fn() - listen to new SMB connections and callback server
 * @p:		arguments to forker thread
 *
 * Return:	0 on success, error number otherwise
 */
static int ksmbd_kthread_fn(void *p)
{
	struct socket *client_sk = NULL;
	struct interface *iface = (struct interface *)p;
	int ret;

	while (!kthread_should_stop()) {
		mutex_lock(&iface->sock_release_lock);
		if (!iface->ksmbd_socket) {
			mutex_unlock(&iface->sock_release_lock);
			break;
		}
		ret = kernel_accept(iface->ksmbd_socket, &client_sk,
				    SOCK_NONBLOCK);
		mutex_unlock(&iface->sock_release_lock);
		if (ret) {
			if (ret == -EAGAIN)
				/* check for new connections every 100 msecs */
				schedule_timeout_interruptible(HZ / 10);
			continue;
		}

		if (server_conf.max_connections &&
		    atomic_inc_return(&active_num_conn) >= server_conf.max_connections) {
			pr_info_ratelimited("Limit the maximum number of connections(%u)\n",
					    atomic_read(&active_num_conn));
			atomic_dec(&active_num_conn);
			sock_release(client_sk);
			continue;
		}

		ksmbd_debug(CONN, "connect success: accepted new connection\n");
		client_sk->sk->sk_rcvtimeo = KSMBD_TCP_RECV_TIMEOUT;
		client_sk->sk->sk_sndtimeo = KSMBD_TCP_SEND_TIMEOUT;

		ksmbd_tcp_new_connection(client_sk);
	}

	ksmbd_debug(CONN, "releasing socket\n");
	return 0;
}

/**
 * ksmbd_tcp_run_kthread() - start forker thread
 * @iface: pointer to struct interface
 *
 * start forker thread(ksmbd/0) at module init time to listen
 * on port 445 for new SMB connection requests. It creates per connection
 * server threads(ksmbd/x)
 *
 * Return:	0 on success or error number
 */
static int ksmbd_tcp_run_kthread(struct interface *iface)
{
	int rc;
	struct task_struct *kthread;

	kthread = kthread_run(ksmbd_kthread_fn, (void *)iface, "ksmbd-%s",
			      iface->name);
	if (IS_ERR(kthread)) {
		rc = PTR_ERR(kthread);
		return rc;
	}
	iface->ksmbd_kthread = kthread;

	return 0;
}

/**
 * ksmbd_tcp_readv() - read data from socket in given iovec
 * @t:			TCP transport instance
 * @iov_orig:		base IO vector
 * @nr_segs:		number of segments in base iov
 * @to_read:		number of bytes to read from socket
 * @max_retries:	maximum retry count
 *
 * Return:	on success return number of bytes read from socket,
 *		otherwise return error number
 */
static int ksmbd_tcp_readv(struct tcp_transport *t, struct kvec *iov_orig,
			   unsigned int nr_segs, unsigned int to_read,
			   int max_retries)
{
	int length = 0;
	int total_read;
	unsigned int segs;
	struct msghdr ksmbd_msg;
	struct kvec *iov;
	struct ksmbd_conn *conn = KSMBD_TRANS(t)->conn;

	iov = get_conn_iovec(t, nr_segs);
	if (!iov)
		return -ENOMEM;

	ksmbd_msg.msg_control = NULL;
	ksmbd_msg.msg_controllen = 0;

	for (total_read = 0; to_read; total_read += length, to_read -= length) {
		try_to_freeze();

		if (!ksmbd_conn_alive(conn)) {
			total_read = -ESHUTDOWN;
			break;
		}
		segs = kvec_array_init(iov, iov_orig, nr_segs, total_read);

		length = kernel_recvmsg(t->sock, &ksmbd_msg,
					iov, segs, to_read, 0);

		if (length == -EINTR) {
			total_read = -ESHUTDOWN;
			break;
		} else if (ksmbd_conn_need_reconnect(conn)) {
			total_read = -EAGAIN;
			break;
		} else if (length == -ERESTARTSYS || length == -EAGAIN) {
			/*
			 * If max_retries is negative, Allow unlimited
			 * retries to keep connection with inactive sessions.
			 */
			if (max_retries == 0) {
				total_read = length;
				break;
			} else if (max_retries > 0) {
				max_retries--;
			}

			usleep_range(1000, 2000);
			length = 0;
			continue;
		} else if (length <= 0) {
			total_read = length;
			break;
		}
	}
	return total_read;
}

/**
 * ksmbd_tcp_read() - read data from socket in given buffer
 * @t:		TCP transport instance
 * @buf:	buffer to store read data from socket
 * @to_read:	number of bytes to read from socket
 * @max_retries: number of retries if reading from socket fails
 *
 * Return:	on success return number of bytes read from socket,
 *		otherwise return error number
 */
static int ksmbd_tcp_read(struct ksmbd_transport *t, char *buf,
			  unsigned int to_read, int max_retries)
{
	struct kvec iov;

	iov.iov_base = buf;
	iov.iov_len = to_read;

	return ksmbd_tcp_readv(TCP_TRANS(t), &iov, 1, to_read, max_retries);
}

static int ksmbd_tcp_writev(struct ksmbd_transport *t, struct kvec *iov,
			    int nvecs, int size, bool need_invalidate,
			    unsigned int remote_key)

{
	struct msghdr smb_msg = {.msg_flags = MSG_NOSIGNAL};

	return kernel_sendmsg(TCP_TRANS(t)->sock, &smb_msg, iov, nvecs, size);
}

static void ksmbd_tcp_disconnect(struct ksmbd_transport *t)
{
	free_transport(TCP_TRANS(t));
	if (server_conf.max_connections)
		atomic_dec(&active_num_conn);
}

static void tcp_destroy_socket(struct socket *ksmbd_socket)
{
	int ret;

	if (!ksmbd_socket)
		return;

	/* set zero to timeout */
	ksmbd_tcp_rcv_timeout(ksmbd_socket, 0);
	ksmbd_tcp_snd_timeout(ksmbd_socket, 0);

	ret = kernel_sock_shutdown(ksmbd_socket, SHUT_RDWR);
	if (ret)
		pr_err("Failed to shutdown socket: %d\n", ret);
	sock_release(ksmbd_socket);
}

/**
 * create_socket - create socket for ksmbd/0
 * @iface:      interface to bind the created socket to
 *
 * Return:	0 on success, error number otherwise
 */
static int create_socket(struct interface *iface)
{
	int ret;
	struct sockaddr_in6 sin6;
	struct sockaddr_in sin;
	struct socket *ksmbd_socket;
	bool ipv4 = false;

	ret = sock_create(PF_INET6, SOCK_STREAM, IPPROTO_TCP, &ksmbd_socket);
	if (ret) {
		if (ret != -EAFNOSUPPORT)
			pr_err("Can't create socket for ipv6, fallback to ipv4: %d\n", ret);
		ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP,
				  &ksmbd_socket);
		if (ret) {
			pr_err("Can't create socket for ipv4: %d\n", ret);
			goto out_clear;
		}

		sin.sin_family = PF_INET;
		sin.sin_addr.s_addr = htonl(INADDR_ANY);
		sin.sin_port = htons(server_conf.tcp_port);
		ipv4 = true;
	} else {
		sin6.sin6_family = PF_INET6;
		sin6.sin6_addr = in6addr_any;
		sin6.sin6_port = htons(server_conf.tcp_port);
	}

	ksmbd_tcp_nodelay(ksmbd_socket);
	ksmbd_tcp_reuseaddr(ksmbd_socket);

	ret = sock_setsockopt(ksmbd_socket,
			      SOL_SOCKET,
			      SO_BINDTODEVICE,
			      KERNEL_SOCKPTR(iface->name),
			      strlen(iface->name));
	if (ret != -ENODEV && ret < 0) {
		pr_err("Failed to set SO_BINDTODEVICE: %d\n", ret);
		goto out_error;
	}

	if (ipv4)
		ret = kernel_bind(ksmbd_socket, (struct sockaddr *)&sin,
				  sizeof(sin));
	else
		ret = kernel_bind(ksmbd_socket, (struct sockaddr *)&sin6,
				  sizeof(sin6));
	if (ret) {
		pr_err("Failed to bind socket: %d\n", ret);
		goto out_error;
	}

	ksmbd_socket->sk->sk_rcvtimeo = KSMBD_TCP_RECV_TIMEOUT;
	ksmbd_socket->sk->sk_sndtimeo = KSMBD_TCP_SEND_TIMEOUT;

	ret = kernel_listen(ksmbd_socket, KSMBD_SOCKET_BACKLOG);
	if (ret) {
		pr_err("Port listen() error: %d\n", ret);
		goto out_error;
	}

	iface->ksmbd_socket = ksmbd_socket;
	ret = ksmbd_tcp_run_kthread(iface);
	if (ret) {
		pr_err("Can't start ksmbd main kthread: %d\n", ret);
		goto out_error;
	}
	iface->state = IFACE_STATE_CONFIGURED;

	return 0;

out_error:
	tcp_destroy_socket(ksmbd_socket);
out_clear:
	iface->ksmbd_socket = NULL;
	return ret;
}

static int ksmbd_netdev_event(struct notifier_block *nb, unsigned long event,
			      void *ptr)
{
	struct net_device *netdev = netdev_notifier_info_to_dev(ptr);
	struct interface *iface;
	int ret, found = 0;

	switch (event) {
	case NETDEV_UP:
		if (netif_is_bridge_port(netdev))
			return NOTIFY_OK;

		list_for_each_entry(iface, &iface_list, entry) {
			if (!strcmp(iface->name, netdev->name)) {
				found = 1;
				if (iface->state != IFACE_STATE_DOWN)
					break;
				ret = create_socket(iface);
				if (ret)
					return NOTIFY_OK;
				break;
			}
		}
		if (!found && bind_additional_ifaces) {
			iface = alloc_iface(kstrdup(netdev->name, GFP_KERNEL));
			if (!iface)
				return NOTIFY_OK;
			ret = create_socket(iface);
			if (ret)
				break;
		}
		break;
	case NETDEV_DOWN:
		list_for_each_entry(iface, &iface_list, entry) {
			if (!strcmp(iface->name, netdev->name) &&
			    iface->state == IFACE_STATE_CONFIGURED) {
				tcp_stop_kthread(iface->ksmbd_kthread);
				iface->ksmbd_kthread = NULL;
				mutex_lock(&iface->sock_release_lock);
				tcp_destroy_socket(iface->ksmbd_socket);
				iface->ksmbd_socket = NULL;
				mutex_unlock(&iface->sock_release_lock);

				iface->state = IFACE_STATE_DOWN;
				break;
			}
		}
		break;
	}

	return NOTIFY_DONE;
}

static struct notifier_block ksmbd_netdev_notifier = {
	.notifier_call = ksmbd_netdev_event,
};

int ksmbd_tcp_init(void)
{
	register_netdevice_notifier(&ksmbd_netdev_notifier);

	return 0;
}

static void tcp_stop_kthread(struct task_struct *kthread)
{
	int ret;

	if (!kthread)
		return;

	ret = kthread_stop(kthread);
	if (ret)
		pr_err("failed to stop forker thread\n");
}

void ksmbd_tcp_destroy(void)
{
	struct interface *iface, *tmp;

	unregister_netdevice_notifier(&ksmbd_netdev_notifier);

	list_for_each_entry_safe(iface, tmp, &iface_list, entry) {
		list_del(&iface->entry);
		kfree(iface->name);
		kfree(iface);
	}
}

static struct interface *alloc_iface(char *ifname)
{
	struct interface *iface;

	if (!ifname)
		return NULL;

	iface = kzalloc(sizeof(struct interface), GFP_KERNEL);
	if (!iface) {
		kfree(ifname);
		return NULL;
	}

	iface->name = ifname;
	iface->state = IFACE_STATE_DOWN;
	list_add(&iface->entry, &iface_list);
	mutex_init(&iface->sock_release_lock);
	return iface;
}

int ksmbd_tcp_set_interfaces(char *ifc_list, int ifc_list_sz)
{
	int sz = 0;

	if (!ifc_list_sz) {
		struct net_device *netdev;

		rtnl_lock();
		for_each_netdev(&init_net, netdev) {
			if (netif_is_bridge_port(netdev))
				continue;
			if (!alloc_iface(kstrdup(netdev->name, GFP_KERNEL)))
				return -ENOMEM;
		}
		rtnl_unlock();
		bind_additional_ifaces = 1;
		return 0;
	}

	while (ifc_list_sz > 0) {
		if (!alloc_iface(kstrdup(ifc_list, GFP_KERNEL)))
			return -ENOMEM;

		sz = strlen(ifc_list);
		if (!sz)
			break;

		ifc_list += sz + 1;
		ifc_list_sz -= (sz + 1);
	}

	bind_additional_ifaces = 0;

	return 0;
}

static struct ksmbd_transport_ops ksmbd_tcp_transport_ops = {
	.read		= ksmbd_tcp_read,
	.writev		= ksmbd_tcp_writev,
	.disconnect	= ksmbd_tcp_disconnect,
};